Joaquin Phoenix, Acting in His Best Interest?

Oh, Joaquin. It's been an antic few months for the Oscar nominee, who was poised on the brink of first-name-only superstardom -- before announcing he's quit acting to pursue a career as a rapper.

From there: He grew a bushy homeless-guy beard, started moping around in dark shades. Gave a weird Las Vegas performance -- brief, incoherent, before he fell off the stage. That now-infamous David Letterman interview -- halting, spacey, unresponsive. Wednesday night in Miami, he took the stage four hours late, disheveled, rapped unintelligibly -- then jumped into the crowd to confront a heckler. Security guards hustled Phoenix out.

Is Joaquin Phoenix really in a meltdown? Or is this a shtick, a gag, an ingenious publicity stunt? We consulted a panel of D.C. professionals who would know: actors.

They agree: It's an act. Here's why.

Kate Debelack (of Shakespeare Theatre's "Ion"): "It's sooo staged. It's only happening when there are video cameras present. He's got a specific way of moving that's different than what we've seen of him before -- it's very much a character. ... He dropped character a bit: He laughed back at Letterman, then immediately went back to being sullen."

Casie Platt (of Signature Theatre's "The Little Dog Laughed"): "I noticed as [the interview] was over, Joaquin stood up with his back to the cameras, took off his glasses, and with a smirk shook Letterman's hand, and Dave seemed in on the joke. ... This is the perfect way to market a movie long before it comes out."

Jason Linkins (of Rorschach Theatre; media writer for the Huffington Post): "I'd say Phoenix is doing an all-right job keeping this act of his airtight ... but he's basically just walking around, acting really convincingly addled, and that's just not that hard."